Tri-Five Big-Block Install - Fat Rat In A Little Hole

Droppin' In A 572-inch Monster

It seems as if during every commercial break, at least one company throws out the "We're the leader in today's technology" type of line. Is it true? We have no idea; after all, what do we know about the molecular anatomy of fabric softeners? Get us in the auto industry and we have a pretty good idea of who's trailblazing. One such shop is D&P Classic Chevy in Huntington Beach, California.

Owner Darryl Nance and crew are always up on the latest trends, especially when it comes to '55-'57 Chevys. In short, Tri-Fives are D&P's forte. More Tri-Fives roll through the doors of D&P than 18-year-olds at the beach on a Friday night. Whether it's a top-of-the-line suspension, A/C installs, LS1 motors, big brakes, or a hula dancer on the dash, D&P has ventured in all areas. But just like the commercials, once you think everything has been tackled, something new pops up.

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This D&P customer ordered the ZZ572/620 Deluxe crate engine from GM Performance Parts. The Deluxe version includes the base ZZ572/620 engine, plus the following items: aluminum water pump, 850-cfm Demon carburetor, flexplate, HEI distributor, aluminum intake manifold, and red plug wires and looms. But it all boils down to power, which weighs in at 620 hp at 5,500 rpm and 650 lb-ft at 4,500 rpm. Before all that power can be dropped in, a few modifications are necessary. For one, you can see how shallow the firewall's bellhousing tunnel is. Because of this, blistering the firewall is a must.

Because Tri-Fives are such hunks of mass it takes a lot to get them up and moving; for that reason one of the more popular setups for Tri-Fives is to drop in a GM Performance Parts 502 Ram Jet motor. The popularity of the 502 over the past few years has prompted aftermarket manufacturers to develop parts to make the swap just another day in the driveway. However, since GMPP has recently released the 572 crate motor, it's a different story. It's not that it couldn't be done, but picking up a catalog and ordering the parts to bang it out just wasn't possible-until now.

Technically, dropping a GMPP 572 is just like any other motor swap, but the problem is the 572 is big and space is limited, so there are a few trouble areas. One of the biggest concerns on stuffing the giant-sized Rat in a car is what to do about headers. The 502 headers won't fit the 572 motor, and on top of that, there isn't much room to work with around there. To help solve the problem, Darryl contacted Doug's Headers. Together they designed a header that will not only fit the application, but actually works, too.

Another obstacle was the oil pans. You have to find an oil pan that not only fits the motor but won't interfere with the crossmember, steering racks, and who knows whatever else. Once again, the aftermarket industry has stepped up. Milodon now offers an oil pan that bolts right up to the 572 with no modifications necessary to drop the motor into a '55-'57 Chevy.

Finally, the last step of dropping a 572 is blistering the firewall. Because the 572 has a bigger mass than the 502, it doesn't quite fit in the engine bay. Right where the valve covers meet the firewall, blisters need to be fabricated into the sheetmetal. Skill-wise, the hardest part of the swap is fabricating the blisters. But on the flip side, making things easier is that with D&P, this swap is just a few phone calls away. You can simply give D&P a buzz and they can ship you the new headers and oil pan; as for the motor you're gonna have to call GMPP. If you're mechanically challenged-or short on time-D&P will do the entire install for you. To get a bird's-eye view of what it takes to drop in the new 572, we took a trip down to D&P's place of business where they were in mid-throw of dropping GM's biggest Rat into a customers '56 Bel Air. Check it out!

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Other than what has been pointed out here, dropping in a 572 is just like dropping in any motor. All that's left to do is install fenders, core supports, grille, and all the other stops along the way. Then it's time to hit the streets and light 'em up!

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Tri-Five Big-Block Install - Fat Rat In A Little Hole

This D&P customer ordered the ZZ572/620 Deluxe crate engine from GM Performance Parts. The Deluxe version includes the base ZZ572/620 engine, plus the following items: aluminum water pump, 850-cfm Demon carburetor, flexplate, HEI distributor, aluminum intake manifold, and red plug wires and looms. But it all boils down to power, which weighs in at 620 hp at 5,500 rpm and 650 lb-ft at 4,500 rpm. Before all that power can be dropped in, a few modifications are necessary. For one, you can see how shallow the firewall's bellhousing tunnel is. Because of this, blistering the firewall is a must.

The left and right corners of the firewall's bellhousing tunnel need to be blistered. What is a blister? It's an indentation in the firewall in order for the valve covers to tuck up into and allow for a proper engine fit. You can see where Darryl's crew has blistered the firewall. This would also be a good time to go ahead and smooth the firewall.

With the new oil pan installed on the 572 engine, Mike and Kevin of D&P dropped the Rat in between the framerails. As for motor mounts, any big-block motor mounts will work.

Once the job is handled, the firewall needs to be prepped and repainted.

Here's a closer look at the new Milodon oil pan that fits the application.

The new GMPP 572 motor is going to exhale through this Doug's Headers exhaust system. The exhaust system is also equipped with electronic cutouts, just in case anyone wants to play.

The Doug's headers were specially made for dropping a 572 into a Tri-Five. Doug's and D&P worked in correlation to develop a header that fits and works. Here, you can see that every necessary step was made, and no corners were cut. For example, check out the pre-fabbed dimple on the driver-side header to clear the steering box.

With the new motor in place, Mike installed the headers.

Because of the excellent fitment, there was no banging, bending, or even cussing. Just simply put them in place and bolt 'em up.

Check out how that dimple allows the header to fit between the block and steering box.

This 1956 Chevrolet Nomad is a custom Tri-Five station wagon which has undergone a detailed restoration and is powered by a GM Performance Parts 350ci ZZ4 crate engine - Super Chevy Magazine » Read More